Many investment cases have recently been published intending to show the value of new health investments, but without consistent methodological approaches.To conduct a scoping review of existing investment cases (using vaccines and immunization programs as an example), identify common characteristics that define these investment cases, and examine their role within the broader context of the vaccine development and introduction.A systematic search was conducted from January 1980 to November 2017 to identify investment cases in the area of vaccines and immunization programs from gray literature and electronic bibliographic databases. Investment case outcomes, objectives, key variables, target audiences, and funding sources were extracted and analyzed according to their reporting frequency.We found 24 investment cases, and most of them aim to provide information for decisions (12 cases) or advocate for a specific agenda (9 cases). Outcomes presented fell into 4 broad categories-burden of disease, cost of investment, impact of investment, and other considerations for implementation. Number of deaths averted (70%), incremental cost-effectiveness ratios (67%), and reduction in health and socioeconomic inequalities (54%) were the most frequently reported outcome measures for impact of investment. Health system capacity (79%) and vaccine financing landscape (75%) were the most common considerations for implementation. A sizable proportion (41.4%) of investment cases did not reveal their funding sources.This review describes information that is critical to decision making about resource mobilization and allocation concerning vaccines. Global efforts to harmonize investment cases more broadly will increase transparency and comparability.